fix: preserve unrelated resume during delete

frontend/src/shell/AppShell.session-mgmt.test.tsx

@@ -590,6 +590,54 @@ test("deleting another session does not invalidate a pending Resume", async () =
   expect(screen.getByTestId("session-item-s1")).toHaveAttribute("data-active", "true");
 });
 
+test("deleting active A preserves a pending Resume for different session B", async () => {
+  const other = {
+    ...LIST[0], id: "s3", question: "Attiva tre", group: null,
+    created_at: "2026-01-03T00:00:00Z",
+  };
+  const s3ResumeGate = deferred();
+  const s3ResumeStarted = deferred();
+  server.use(
+    http.get("http://localhost:8787/sessions", () => HttpResponse.json([LIST[0], other])),
+    http.post("http://localhost:8787/sessions/:id/resume", async ({ params }) => {
+      const id = params.id as string;
+      if (id === "s3") {
+        s3ResumeStarted.resolve();
+        await s3ResumeGate.promise;
+      }
+      return resumeResult(id);
+    }),
+    http.get("http://localhost:8787/sessions/:id", ({ params }) =>
+      HttpResponse.json({ id: params.id, status: "open", phase: params.id === "s3" ? 3 : 1 })),
+    http.delete("http://localhost:8787/sessions/:id", ({ params }) => {
+      expect(params.id).toBe("s1");
+      return new HttpResponse(null, { status: 204 });
+    }),
+  );
+  wrap();
+
+  await userEvent.click(await screen.findByText("Attiva uno"));
+  await userEvent.click(await screen.findByRole("button", { name: /resume/i }));
+  await waitFor(() => expect(FakeEventSource.instances).toHaveLength(1));
+  const sourceA = FakeEventSource.instances[0];
+  expect(screen.getByTestId("session-item-s1")).toHaveAttribute("data-active", "true");
+
+  await userEvent.click(screen.getByText("Attiva tre"));
+  await userEvent.click(await screen.findByRole("button", { name: /resume/i }));
+  await s3ResumeStarted.promise;
+  screen.getByRole("checkbox", { name: "Select Attiva uno" }).focus();
+  await userEvent.keyboard(" ");
+  await userEvent.click(await screen.findByRole("button", { name: "Delete 1 selected sessions" }));
+  await waitFor(() => expect(sourceA.closed).toBe(true));
+  expect(screen.getByTestId("session-item-s1")).toHaveAttribute("data-active", "false");
+
+  s3ResumeGate.resolve();
+
+  await waitFor(() => expect(FakeEventSource.instances).toHaveLength(2));
+  expect(FakeEventSource.instances[1].url).toContain("/sessions/s3/events");
+  expect(screen.getByTestId("session-item-s3")).toHaveAttribute("data-active", "true");
+});
+
 test("a failed Delete does not invalidate a pending Resume for its target", async () => {
   const resumeGate = deferred();
   const resumeStarted = deferred();

frontend/src/shell/AppShell.tsx

@@ -247,7 +247,7 @@ export function AppShell() {
       );
       const deletedActiveSession = deletedIds.has(activeSessionIdRef.current ?? "");
       const deletedResumeTarget = deletedIds.has(latestResumeIntentRef.current?.id ?? "");
-      if (deletedActiveSession || deletedResumeTarget) invalidateResumeIntent();
+      if (deletedResumeTarget) invalidateResumeIntent();
       if (deletedIds.has(panelSession?.id ?? "")) setPanelSession(null);
       if (deletedActiveSession) { resetSession(); selectActiveSession(null); }
       setSelectedSessionIds((current) => new Set([...current].filter((id) => !deletedIds.has(id))));